 <ul class="nav nav-tabs" style="margin-left: -1px;">
    <li>
      <a href="{:U('index')}" class="tab_index">班级课程设置</a>
    </li>
    <li>
      <a href="{:U('course')}" class="tab_course">年级课程设置</a>
    </li>
    <li>
      <a href="{:U('setCurClass')}" class="tab_setcurclass">设置当前班级</a>
    </li>
    
    <li>
      <a href="{:U('Score/score_asc')}" class="tab_score">积分排行榜</a>
    </li>
  </ul>

 <script>
    $(function () {
        $('.tab_' + "{$now_tab}").parent().addClass('active');
    });
</script>